The survival rate of lung cancer among Americans has increased from 20.8% to 23.7% over the past five years. If there is one thing awareness about lung cancer — and every other type of cancer — tells us, it’s the fact that most cancers wouldn’t be detected until it had spread to an advanced stage.
This is where the need for screening becomes more pressing. Through screening, doctors can detect lung cancer even when the symptoms have not surfaced, thereby making treatment easier. Thus, a low-dose Computerized Tomography (CT) scan for lung cancer can be crucial for survival.
What Do CT Scans of the Lung Show?
A low-dose CT scan of the lung is a non-invasive and painless procedure involving low-dose X-rays to screen your lungs for cancer. What makes a low-dose CT scan better than a traditional scan? The difference is in the details.
Simply put, a CT scan of the lung shows more detailed information than conventional X-rays. That additional information goes a long way in making it possible to diagnose and manage lung cancer earlier.
It also uses less ionizing than the traditional scans, making it a healthier option for patients.
It can detect pulmonary nodules or tumors, i.e., a collection of abnormal lung tissue, which may be early signs of lung cancer. However, it is essential to state that finding pulmonary nodules doesn’t mean you have cancer because not all these nodules are cancerous.
Some nodules are malignant (cancerous), while others are benign (noncancerous). Early detection of malignant nodules with CT lung screening makes it possible to treat the cancer cells when cancer can be localized to the lungs and prevented from spreading.
Who Should Be Screened for Lung Cancer?
There are different recommendations as to who should be screened for lung cancer. However, one thing in common among these recommendations is that people who have a history of smoking need screening.
According to the U.S. Preventive Services Task Force, yearly lung cancer screening is recommended for:
- People between 50 and 80 years old
- Those who have a 20-pack year or more of smoking history
- Those who smoke now or have stopped smoking within the past 15 years
In this sense, a “pack year” means smoking an average of one pack of cigarettes per day for one year. Going by this, a person with a 20-pack year history could be someone who smoked one pack per day for 20 years or two packs per day for ten years.
The American Cancer Society recommends yearly CT scans for lungs for those who are:
- Between 55 to 74 years old
- In fairly good health
- Who currently smoke or have quit smoking in the past 15 years and with at least a 30 pack-year smoking history which could mean smoking one pack per day for 30 years or two packs per day for 15 years
Beyond these high-risk individuals with exposure to smoking, people with a history of lung cancer should also consider regular screening. If you have also been exposed to asbestos in the past, your doctor can recommend the screening for you.
How is a Lung Scan Performed?
A low-dose chest CT scan takes only a few minutes, although your appointment may last for about half an hour. You will lay on your back on a long table during a low-dose CT scan. Medical professionals expect you to remain still as the table slides through the center of the machine that creates images of your lungs. A technologist wouldn’t be with you but would see and hear you during the period.
Initially, the table passes through the machine to determine the starting point for the scan, and when the machine is ready to start, a technologist will tell you to hold your breath for a brief period to get a clear image of your lungs. The table moves quickly through the machine as it creates the images.
Lung Cancer Screening Risks
As beneficial as lung cancer screening is, it still comes with its risks.
Low-dose chest CT scan radiant exposure may increase the risk of cancer. It is especially true for younger people or people who only have a low risk. These people are more likely to develop lung cancer due to low-dose chest CT scan radiant exposure.
In addition to the low dose chest CT scan radiant exposure risk, you may also need to undergo additional scans and follow-up tests if the initial scan results become suspicious. In this case, you get exposed to more radiation, which comes with different health risks. If the results of the other tests show there is no issue, it means you have been exposed to unnecessary risks, which you would have avoided if you didn’t have a low-dose CT scan of the lung in the first place.
Aside from the low-dose chest CT scan radiant exposure risk and the need to undergo follow-up tests, another risk is that the scan may reveal that the lung cancer is too advanced for a cure.
How to Prepare for a CT Scan of the Lungs
You don’t need to do anything special to prepare for a low-dose CT scan of the lungs, but there are a few things we want you to pay attention to. The first is to let your doctor know if you have a respiratory tract infection. It is essential to make this known because the respiratory infection can cause an abnormality on the CT scan (for instance, a false-positive result), requiring additional tests to investigate. We always recommend that you delay your screening till the signs and symptoms of the infection disappear.
You should also avoid wearing metals such as jewelry, glasses, and dentures when going for a CT scan, as these can interfere with the imaging.
How Accurate is a CT Scan for Lung Cancer?
According to the National Lung Screening Trial, approximately 250 out of 1,000 high-risk patients screened who do not have cancer will be told their low-dose CT scans show an abnormality that may be cancer.
This study also reveals a high level of false positives with lung cancer screening. The study found that about 59.7% of the current or former smokers patients screened for lung cancer with low dose CT scan had a positive result. However, 97.5% of them were false-positive results. Thus, we always tell our patients that there is a possibility of receiving a positive result which may not be lung cancer.
How Often Should Lung Cancer Screening Be Done?
As earlier stated, the U.S. Preventive Services Task Force recommends yearly lung cancer screening for people between 50 and 80 years old, have a 20-pack year or more of smoking history, and smoke now or have stopped smoking within the past 15 years.
However, the task force recommends that you stop yearly lung cancer screening when you turn 81 years old, haven’t smoked in 15 or more years, or develop a health problem that makes you unwilling or unable to have surgery the screening detects lung cancer.
If your CT scan shows that you have benign nodules, we highly recommend you go for yearly screenings to ensure that the nodules do not grow.